This invention relates generally to turbine engines, and more specifically to a method and apparatus for coupling a wear-resistant material to a turbine engine component.
At least some known gas turbine engines include a forward fan, a core engine, and a power turbine. The core engine includes at least one compressor that provides pressurized air to a combustor wherein the air is mixed with fuel and ignited for generating hot combustion gases. The combustion gases flow downstream to one or more turbines that extract energy therefrom to power the compressor and provide useful work, such as powering an aircraft. A turbine section may include a stationary turbine nozzle positioned at the outlet of the combustor for channeling combustion gases into a turbine rotor disposed downstream thereof. At least some known turbine rotors include a plurality of circumferentially spaced apart turbine blades extending radially outwardly from a rotor disk that rotates about the centerline axis of the engine.
The turbine section also includes a shroud assembly coupled downstream from the turbine nozzle. The shroud assembly circumscribes the turbine rotor and defines an outer boundary for the hot combustion gases flowing through the turbine. At least some known shroud assemblies include a shroud hanger member that is coupled to an outer casing of the engine to provide support to a plurality of shrouds positioned adjacent to the tips of the high-pressure turbine blades. At least some known shroud hanger members include an axially forward flange that is positioned in compressive engagement to a mating surface on the circumferentially spaced apart nozzle segments.
The combination of differing rates of thermal expansion between adjacently coupled shroud hangers and turbine nozzle segments, the dynamic effects of the engine, for example, vibration and/or high compression contact between shroud hangers and turbine nozzle segments may result in wear of the shroud hanger at the interface. Over time, a worn surface may adversely affect turbine operating performance, and/or shorten the engine maintenance cycle-time. A wear-resistant coating, such as a thermal spray of a wear-resistant alloy, may be applied to the shroud hanger during fabrication to facilitate minimizing wear. However, such coatings may be susceptible to chipping, and a high level of manufacturing effort and cycle-time impact due to thermal spray processes may result in relatively high manufacturing costs.